Incontinence detection pad validation apparatus and method

ABSTRACT

An incontinence detection pad has an RFID tag in which an authentication code, such as an electronic product code (EPC), is stored. A reader in wireless communication with the RFID tag of the incontinence detection pad verifies that the incontinence detection pad is an authorized detection pad. Thus, unauthorized incontinence detection pads that do not have the proper authentication code are not able to be used in an incontinence detection system.

The present application is a continuation-in-part of U.S. applicationSer. No. 15/596,036, which was filed May 16, 2017, which is acontinuation-in-part of International Application No. PCT/US2016/062167,which was filed Nov. 16, 2016, which claims the benefit, under 35 U.S.C.§ 119(e), of U.S. Provisional Application No. 62/255,592, which wasfiled Nov. 16, 2015, and each of which is hereby incorporated byreference herein in its entirety.

BACKGROUND

The present disclosure relates to incontinence detection systems andparticularly, to incontinence detection systems that use a pad beneath aperson lying in a patient bed. More particularly, the present disclosurerelates to incontinence detection systems that are able to communicatewirelessly between the pad and a reader on the patient bed.

Incontinence detection systems that have incontinence detection padsplaced beneath a patient on a patient bed are known. For example, U.S.Pat. No. 5,537,095 discloses an incontinence detection pad havingelectrical circuitry that couples via a wired connection to a controllerof a patient bed. Recent efforts have involved the development ofwireless communication between the circuitry of the incontinencedetection and a reader on a patient bed. The antennae in some such priorsystems are individually powered by a reader to energize a passive RFIDchip on the incontinence detection pad and to read backscattered datasent from the passive RFID chip back to the reader via the antennae.

In the known wireless incontinence detection pad systems, signal tointerfere (S/I) ratio issues are prevalent. For example, when amonostatic architecture using a hybrid directional coupler to providereceiver isolation from the transmitter and to allow simultaneoustransmission and reception on the same antenna, the coupling between thetransmitter and receiver ports of the hybrid coupler is about −10decibels (dB). This means that 90% of the received signal does not endup in the receiver. Furthermore, if the antenna impedance deviates fromthe transmission line characteristic impedance, the power reflected fromthe antenna is coupled into the receiver input and is much stronger thanthe backscattered signal from the RFID tag, which creates the situationwhere the receiver must reject a very strong signal near the signal ofinterest in order to detect and demodulate only the signal of interest,which in the case of an EPC 2 compliant tag, is 256 kilohertz (kHz) awayfrom the carrier. In such situations the S/I ratio can be on the orderof 50 dB. An alternative known architecture is the use of a circulatorwhich couples the transmitter and receiver, functionally, in a similarway as a hybrid coupler. However, the S/I ratio using a circulator isonly about 1.6 dB better than the hybrid coupler approach.

Other interfering signals include forward power coupling into thereceiver port, which can be 5 dB higher than the tag backscatteredsignal, and power reflected from the RF forward power, which can be 34dB stronger than the backscattered signal. All of these signals add intothe front end of the receiver, which subjects it to overload andintermodulation distortion products which may further impact theperformance of the receiver. In other words, because there is a strongsignal close in frequency to a weak signal, it is difficult to detectthe weak signal. A further concern is that RFID systems that are locatedin close proximity to a patient's body experience communication channeldegradation due to the interaction of the biological tissue and bodyfluids with the RFID tag.

Based on the foregoing, it should be apparent that there is an ongoingneed for improved electrical architecture in wireless incontinencedetection pad systems used on patient support apparatuses such aspatient beds.

SUMMARY

The present application discloses one or more of the features recited inthe appended claims and/or the following features which, alone or in anycombination, may comprise patentable subject matter:

According to the present disclosure, an incontinence detection systemmay include an incontinence detection pad for placement beneath a personto be monitored. The incontinence detection pad may have a passive radiofrequency identification (RFID) tag. A reader may be provided and aplurality of antennae may be coupled to the reader. The reader mayinclude a bistatic radio frequency (RF) switch matrix which may beoperable to establish a first antenna of the plurality of antennae as atransmit antenna that may be used to wirelessly energize the passiveRFID tag and to establish a second antennae of the plurality of antennaeas a receive antenna that may be used to read backscattered data thatmay be emitted from the passive RFID tag. The first and second antennaemay be situated in respective housings that are spaced apart from eachother.

In some embodiments, the plurality of antennae may include a thirdantenna and a fourth antenna. The bistatic RF switch matrix may beoperated in a full cycle scanning mode so that each of the first,second, third and fourth antenna may be selectively chosen to beestablished as the transmit antenna and each of the remaining antennamay be selectively cycled through to be the receive antenna such thattwelve transmit antenna and receive antenna combinations may beoperated.

During the full cycle mode, the transmit antenna and receive antennacombinations that may produce valid reads of the RFID tag may be stored.A modified cycle scanning mode then may be determined for operation ofthe bistatic RF switch matrix based on the valid reads such that onlytransmit antenna and receive antenna combinations that produced validreads may be cycled through for a predetermined number of cycles, afterwhich the bistatic RF switch matrix may be once again operated in thefull cycle scanning mode. If no valid reads of the passive RFID tag aredetected during the full cycle scanning mode, then the bistatic RFswitch matrix may continue to operate in the full cycle scanning modeuntil at least one valid read is detected, after which the bistatic RFswitch matrix may be operated in the modified cycle scanning mode.

In some embodiments, the plurality of antennae may be operated by thereader by transmitting using a frequency hopping scheme at a power lessthan or equal to 1 Watt (W). The frequency hopping scheme may use 50distinct frequencies, for example, with each frequency being used onlyonce in a pseudo-random order before any of the 50 frequencies may berepeated. Optionally, the 50 frequencies may lie within a range betweenabout 902 MegaHertz (MHz) and 928 MHz. At least one antenna of theplurality of antennae may comprise a ½ wave ceramic patch antenna. Ifdesired, however, each antenna of the plurality of antennae may comprisea ½ wave ceramic patch antenna.

The incontinence detection system may further include a patient bed thatmay have a frame and a mattress support deck that may be carried by theframe. The mattress support deck may include a head section, a seatsection, and a thigh section. At least the head section and the thighsection may be raiseable and lowerable relative to the frame. The firstand second antennae may be coupled to the head section, the thirdantenna may be coupled to the seat section, and the fourth antenna maybe coupled to the thigh section. Alternatively, the first antenna may becoupled to the head section, the second and third antennae may becoupled to the seat section, and the fourth antenna may be coupled tothe thigh section. Further alternatively, the first antenna may becoupled to the head section, the second antenna may be coupled to theseat section, and the third and fourth antennae may be coupled to thethigh section.

In some embodiments, the incontinence detection may further include apatient bed that may have a frame and a mattress support deck carried bythe frame. The mattress support deck may include a first section and asecond section that each may be raiseable and lowerable relative to theframe. The first section and the second section each may be formed in astep deck arrangement that may have a bottom wall and a side wall thatmay extend generally upwardly from the bottom wall. The first antennaemay be coupled to the bottom wall of the first section, the secondantenna may be coupled to a side wall of the first section, the thirdantenna may be coupled to the bottom wall of the second section, and thefourth antenna may be coupled to the side wall of the second section.

It is within the scope of this disclosure that the incontinencedetection system may further include a patient bed that may have a frameand a mattress support deck carried by the frame. The reader may becoupled to the frame and the plurality of antennae may be coupled to themattress support deck so as to be closer to a first side of the mattresssupport deck than an opposite second side of the mattress support deck.

In some embodiments, the incontinence detection system may furtherinclude an indicator that may be located adjacent a foot end of the bedand that may be operable to indicate that an incontinence event hasoccurred. Optionally, an output port may be located adjacent a head endof the bed and may be connectable to a nurse call system for providingincontinence event data to the nurse call system.

According to the present disclosure, an electrical sheet for anincontinence detection pad may be provided. The electrical sheet mayinclude a layer of material that may be shaped generally as a rectanglethat may have first and second long sides and first and second shortsides. An RFID tag may be coupled to the layer closer to the first shortside than the second short side. First and second electrodes may beprovided on the layer and may be electrically coupled to the RFID tag.The first and second electrodes may include first, second, third andfourth electrode segments that may be generally parallel with the firstand second long sides of the layer. The second and third electrodesegments may be situated between the first and fourth electrodesegments. The second and third electrode segments may be spaced apart bya first distance that may be at least twice a second distance that maybe defined between the first and second electrode segments and betweenthe third and fourth electrode segments.

The first and second electrodes may also provide fifth, sixth, seventhand eighth electrode segments that may be generally parallel with thefirst and second short sides of the layer. The sixth and seventhelectrode segments may be situated between the fifth and eighthelectrode segments. The fifth and sixth electrode segments may be spacedapart by a third distance that may be at least six times a fourthdistance that may be defined between the fifth and sixth electrodesegments and between the seventh and eighth electrode segments.

The fifth and seventh electrode segments may be included as part of thefirst electrode and the sixth and eighth electrode segments may beincluded as part of the second electrode. The first and third electrodesegments may be included as part of the first electrode and wherein thesecond and fourth electrode segments may be included as part of thesecond electrode. The layer may be devoid of any electrode portionsbetween the second and third electrode segments.

In some embodiments, the first distance between the second and thirdelectrode segments may be greater than 30% of a third distance that maybe defined between the first and second long sides of the layer. Forexample, the first distance between the second and third electrodesegments may be greater than 40% of a third distance that may be definedbetween the first and second long sides of the layer. The spacingbetween the second and third electrode segments is intended to besufficiently large to prevent a gel or ointment applied to a patient'sbuttocks and/or sacral region from providing an electrically conductivepath between the second and third electrode segments that are orientedparallel with the first and second long sides of the layer.

According to a further aspect of this disclosure, an electrical sheetfor an incontinence detection pad is provided. The electrical sheet mayinclude a layer of material shaped generally as a rectangle having firstand second long sides and first and second short sides. An RFID tag maybe coupled to the layer closer to the first short side than the secondshort side. First and second electrodes may be provided on the layer andmay be electrically coupled to the RFID tag. The first and secondelectrodes may include first, second, third and fourth electrodesegments that may be generally parallel with the first and second shortsides of the layer. The second and third electrode segments may besituated between the first and fourth electrode segments. The second andthird electrode segments may be spaced apart by a first distance thatmay be at least six times a second distance that may be defined betweenthe first and second electrode segments and between the third and fourthelectrode segments.

The layer may be devoid of any electrode portions between the second andthird electrode segments. The first distance between the second andthird electrode segments may be greater than 50% of a third distancedefined between the first and second short sides of the layer. Thespacing between the second and third electrode segments is intended tobe sufficiently large to prevent a gel or ointment applied to apatient's buttocks and/or sacral region from providing an electricallyconductive path between the second and third electrode segments that areoriented parallel with the first and second short sides of the layer.

In some embodiments, the electrical sheet may further have at least oneicon that may include a water droplet with WiFi curves and that may beprinted on a surface of the layer that may be opposite from a surface onwhich the first and second electrodes may be provided. Optionally, thelayer may include a first substrate that may be made of a fluidimpermeable material and a second substrate that may be made of anonwoven material. The first and second electrodes may be located on thefluid impermeable material and the at least one icon may be located onthe nonwoven material.

For each of the above aspects and embodiments contemplated herein, areader of an incontinence detection system may be equipped with an802.11 wireless communication capability for communication with awireless access point which may, in turn, be connected via a network toa remote computer, such as a remote computer or server of a ClinicalWorkflow Solutions (CWS) medical data management system. The CWS systemmay or may not be included as part of nurse call system, for example.The reader may send tag identification (ID) and an encrypted ID, both ofwhich may be received by the reader from a RFID tag of an incontinencedetection pad, to the remote server of the CWS system for remotevalidation of the incontinence detection pad that may be placed on abed. More than one pad may be placed on the bed 10 in which case thereader may receive more than one tag ID and more than one encrypted ID.The CWS system may perform decryption remotely and may compare the tagID and the data that may be derived from decrypting the encrypted IDfrom the tag to complete the validation. If desired, the data sent fromthe reader may be protected against transmission errors corrupting thedata with standard Internet Protocol error checking algorithms and/oradditional error detection that may be applied by the reader at the bed.

By moving the validation operation to a remote site, such as a computeror server of CWS system that may have internet connectivity may resultin a number of advantages. Firstly, the processor of the reader at thebed may not have the computational resources either in terms of memoryor CPU cycles to accomplish the decryption locally. Secondly, theencryption algorithm may be changed at will and the algorithm that maybe used may be determined by the tag ID so the deployment in the fieldmay be seamless. The encryption details and private keys may be managedby an online connection to a secure server at another facility (e.g., aserver at the entity which may manufacture or sell the incontinencedetection system and/or the bed), which may enable the modification ofthe private key on an as-needed basis, a periodic change in private keyor the wholesale replacement of the encryption algorithm in a securefashion. In this way, the data generated for pad validation may be donein an entirely secure fashion, and may be done on an as needed basis. Ifit is detected that the private key has become compromised, a newprivate key may be instituted and the pad serial numbers/private key maybe maintained in a database at the CWS server for pad validation.

In some embodiments, the incontinence detection systems and the bed maybe used in home healthcare and other markets outside a traditionalhospital or other healthcare facility. For such markets, the reader maybe constructed with a very limited functionality microprocessor byhaving the high compute resource intensity operations, such asdecryption algorithms, accomplished remotely via any available internetconnection. As a collateral benefit, a service may be used toautomatically bill and send more incontinence pads to a customer (viaprior arrangement), thereby enabling e-commerce business using existinghardware connections. Thus, a server of the CWS system or a server at aremote facility may perform pad usage data collection, may performbilling functions, and/or may generate inventory management data, aswell as provide other notifications to hospitals or home users aboutincontinence detection pad usage. For example, such usage data mayinclude a number of pads used per day, week, and/or month; averageamount of time before a dry pad becomes soiled; average amount of timeafter soiling before the wet pad is removed and/or replaced with a drypad; and number of pads remaining from prior shipment quantity forusage.

Additional features, which alone or in combination with any otherfeature(s), including those listed above and those listed in the claims,may comprise patentable subject matter and will become apparent to thoseskilled in the art upon consideration of the following detaileddescription of illustrative embodiments exemplifying the best mode ofcarrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is a perspective view showing four antenna, a reader, and avisual indicator of an incontinence detection system installed on afirst embodiment of a patient bed with first and second antennae beingcoupled to a head section of the patient bed, a third antenna coupled toa seat section of the patient bed, and a fourth antenna coupled to athigh section of the patient bed and showing, diagrammatically, thereader being coupled electrically to bed control circuitry to sendincontinence detection data via the bed control circuitry to a nursecall output port of the patient bed;

FIG. 2 is a top plan view of the patient bed of FIG. 1 showing dottedboxes indicating some, but not all, possible locations on the head, seatand thigh sections for placement of the four antennae of theincontinence detection system;

FIG. 3 is a perspective view, similar to FIG. 1, showing the fourantennae, the reader, a visual indicator, and an output port of anotherembodiment of an incontinence detection system retrofitted on a secondembodiment of a patient bed with the first and second antennae beingcoupled to a head section of the patient bed and the third and fourthantenna being coupled to a thigh section of the patient bed;

FIG. 4 is a top plan view of a portion of the patient bed of FIG. 3showing the four antennae on the head and thigh sections of the patientbed;

FIG. 5 is a perspective view, similar to FIG. 1, showing the fourantenna, the reader, the visual indicator, and the output port of theincontinence detection system retrofitted on a third embodiment of apatient bed with the first antenna being coupled to a slideable panel ofa head section of the patient bed, the second and third antenna coupledto a seat section of the patient bed, and the fourth antenna coupled toa thigh section of the patient bed;

FIG. 6 is a top plan view of a portion of the patient bed of FIG. 5showing the four antennae on the head, seat and thigh sections of thepatient bed;

FIG. 7 is a diagrammatic view showing distances between each of the fourantennae of the incontinence detection system and an RFID tag of anincontinence detection pad situated between a patient and an uppersurface of a mattress of a patient bed and showing the readercommunicating with a network via wired and wireless datalinks;

FIG. 8 (spanning four sheets) is an electric circuit schematic showingthe reader including a bistatic radio frequency (RF) switch matrix thatcontrols selection of the four antennae in various combinations fordesignating one of the four antennae as a transmitting antenna anddesignation another one of the remaining three antennae as a receivingantennae; and

FIG. 9 is a top plan view of an electrical sheet of an incontinencedetection pad of the incontinence detection system showing a pair ofelectrodes with respective ends terminating at a radio frequencyidentification (RFID) tag mounted on the electrical sheet and showing anenlarged bubble with the RFID tag attached to the electrical sheetwithin a rectangular tag footprint.

DETAILED DESCRIPTION

Referring now to FIGS. 1-7, an incontinence detection system 20 isattached to different types of hospital beds 10. The bed 10 of FIGS. 1and 2 is marketed as the CENTRELLA™ Smart+Bed by Hill-Rom Company, Inc.Further details of bed 10 of FIGS. 1 and 2 can be found in InternationalPatent Application No. PCT/US2016/034908, which was filed May 29, 2016,and which is hereby incorporated by reference herein in its entirety.The bed 10 of FIGS. 3 and 4 is illustrative of the VERSACARE® bedavailable from Hill-Rom Company, Inc. The bed 10 of FIGS. 5 and 6 isillustrative of the PROGRESSA® bed available from Hill-Rom Company, Inc.The bed 10 of FIG. 7 is a generic bed which is shown diagrammatically.

With the exception of bed 10 of FIGS. 1 and 2, which will be discussedbelow, the incontinence detection system 20 includes a reader 12; first,second, third and fourth antennae 13, 14, 15, 16; a visual indicator 18;and an output port 22 as shown in FIGS. 3, 5 and 7. A respective cable23 electrically couples each antenna 13, 14, 15, 16 to reader 12. Acable 25 electrically couples reader 12 to visual indicator 18 and acable 27 electrically couples reader 12 to output port 22. Incontinencedetection system 20 also includes one or more incontinence detectionpads 60 on bed 10. Pads 60 have a moisture absorbing substrate 62 and apassive RFID tag 64 within the substrate 60 as shown diagrammatically inFIG. 7. At least two electrode traces are coupled to the passive RFIDtag and extend therefrom within the substrate as will be discussed belowin connection with FIG. 9.

Reader 12 is operated so that a selected one of antennae 13, 14, 15, 16is established as a transmit antenna and another of antennae 13, 14, 15,16 is established as a receive antenna. As will be described in furtherdetail below, reader 12 is operated to cycle through each antennae 13,14, 15, 16 as being the transmit antenna and to cycle through theremaining three antennae, one at a time, as being the receive antenna.The transmit antenna emits wireless energy to power an RFID chip of RFIDtag 64 and, in response, the RFID tag transmits backscattered data whichis potentially read by the receive antenna. The data indicates whetherthe pad 60 is wet or dry. The pad 60 is considered “wet” if there isenough moisture or liquid, such as incontinence, to bridge a spacebetween the electrode traces and the pad 60 is considered “dry” if thereis insufficient moisture or liquid to bridge the space between theelectrode traces.

Bed 10 of FIGS. 1 and 2 has a mattress support deck 30 with a headsection 32, a seat section 33, a thigh section 34, and an extendable andretractable foot section 36. In the illustrative example, seat section33 is U-shaped and thigh section 34 nests within the cavity formed bythe U-shape of seat section 33. In FIGS. 1 and 2, sections 32, 33, 34,36 are oriented generally horizontally such that the upper surfaces ofsections 32, 33, 34, 36 are generally coplanar with each other. Bed 10of FIGS. 1 and 2 has an upper frame 38 upon which sections 32, 34, 36 ofdeck 30 are supported for pivoting or articulating movement. Seatsection 33 is stationary relative to upper frame 38 in bed 10 of FIGS. 1and 2.

Bed 10 of FIGS. 1 and 2 also has a base frame 40 which is supported on afloor by a set of four casters 42. Bed 10 has a lift system to raise,lower and tilt upper frame 38 relative to base frame 40 as is known inthe art. The lift system is in the form of linkages 41 and motorizedlinear actuators in some embodiments. Bed 10 of FIGS. 1 and 2 has a pairof head end siderails (sometimes referred to as head rails) 44 that aremounted to and move with head section 32 as it is pivotably raised andlowered relative to upper frame 38, a pair of foot end siderails 46(sometimes referred to as foot rails) that are mounted to upper frame38, a headboard 48 removably coupled to an upstanding portion 50 of baseframe 40, and a footboard 52 removably coupled to a foot end portion offoot section 36 which is the extendable and retractable portion of footsection 36. In FIG. 1, the head rail 44 and the foot rail 46 at the leftside of bed 10 have been removed so that reader 12 and antennae 13, 14,15, 16 can be seen.

In the illustrative FIGS. 1 and 2 example of bed 10, antennae 13, 14 arecoupled to head section 32 near the left edge thereof and more towardthe foot end of head section 32. Antenna 14 is coupled to seat section33 near the left edge therefor and more toward the head end of seatsection 33. Antenna 16 is coupled to thigh section 34 near the left edgethereof and more toward the head end of thigh section 34. The placementof antennae 13, 14, 15, 16 on sections 32, 33, 34 is a matter of trialand error based on the locations that produce the best results forreading tags 64 of incontinence detection pads 60 that are used on bed10. Thus, in FIG. 2, a number of dotted boxes 55 are shown to indicate asampling of some, but not all, possible locations on sections 32, 33, 34at which antennae 13, 14, 15, 16 may be placed. In the illustrativeexample, antennae 13, 14, 15, 16 are closer to the left side of bed 10because incontinence detection pad has RFID tag 64 nears its left side.In other embodiments, antennae 13, 14, 15, 16 are coupled to deck 30closer to the right side thereof.

In the illustrative FIGS. 1 and 2 example, cables 23 are routed fromrespective antennae 13, 14, 15, 16 to reader 12 through a space or gap70 formed between a foot end of head section 32 and a head end of seatsection 33. One key difference between the incontinence detection system20 of FIGS. 1 and 2 and those of FIGS. 3-7 is that visual indicator 18,output port 20, and cables 25, 27 are omitted in the FIGS. 1 and 2system 20. Instead, reader 12 is electrically coupled to bed controlcircuitry 72 via a suitable cable 74 as shown diagrammatically in FIG.1.

Bed 10 of FIGS. 1 and 2 has a series of alert lights 76 a, 76 b, 176 c,76 d, 76 e that are included in a foot end frame member 78 of footsection 36 and that are controlled by bed control circuitry 72. Alertlights 76 a-e are similar to those shown and described in InternationalPatent Application No. PCT/US2016/034908 which is already incorporatedby reference herein (see particularly, FIG. 97 along with the relateddiscussion of that document). For purposes of this disclosure, alertlight 76 e is the one that is illuminated in connection with theincontinence detection system 20 of bed 10 of FIGS. 1 and 2. Circuitry72 of bed 10 commands alert light 76 e to shine or illuminate whitelight when reader 12 is turned on but no incontinence detection pad 60is detected. Circuitry 72 of bed 10 commands alert light 76 e to shinegreen light when reader 12 is turned on and is communicating with anincontinence detection pad 60 that is dry, or at least not sufficientlywet to be sensed by the pad 60. Circuitry 72 of bed 10 commands alertlight 76 e to shine yellow (aka amber) light, and to flash in someembodiment, when reader 12 is turned on and is communicating with anincontinence detection pad 60 that is wet.

Bed circuitry 72 is operable to output bed data, including data detectedby the incontinence detection system 20, through a nurse call outputport 80 shown diagrammatically in FIG. 1. Port 80 is a 37-pin connectorin some embodiments, for example. Such 37-pin connectors are knownconnectors which are sometimes used on hospital beds for communicationwith a nurse call system of a healthcare facility. In some embodiments,the incontinence detection information or data, such as data includinginformation regarding whether the incontinence detection pad 60 hasdetected wetness, is transmitted from bed 10 by circuitry 72 via port 80in one or more data packets that also include the other bed data. Inother embodiments, the incontinence detection information is transmittedin one or more data packets that do not include the bed data. That is,the incontinence detection data can be transmitted in the same datapackets as the bed data or in separate packets.

Each antenna 13, 14, 15, 16 is smaller than the two antennae disclosedin International Patent Application No. PCT/US2016/062167, filed Nov.16, 2016, titled “Incontinence Detection Systems for Hospital Beds,” andowned by the same Assignee as the present application. A footprint ofeach antenna 13, 14, 15, 16 is about three inches by three inches.Furthermore, each antenna 13, 14, 15, 16 comprises a ½ wave ceramicpatch antenna. This type of antenna is an improvement over the antennadisclosed in International Patent Application No. PCT/US2016/062167. Inparticular, about 25 to about 30 dB of isolation is achieved by usingthe ½ wave ceramic patch antenna as part of antennae 13, 14, 15, 16which represents better isolation by about 15 to about 25 dB as comparedto a directional coupler design. This is because the reflected powersignal back from the transmit antenna is no longer coupled into thereceiver of reader 12. The receiver circuitry of reader 12 is isolatedfrom the transmitter circuitry.

Referring now to FIGS. 3 and 4, the illustrative bed 10 is similar tothat of FIGS. 1 and 2 such that like reference numbers are used todenote like components of these beds. The description above of bed 10 ofFIGS. 1 and 2 is equally applicable to bed 10 of FIGS. 3 and 4 exceptwhere noted in the description that follows. Bed 10 of FIGS. 3 and 4 hasa mattress support deck 30 with a dished head section 32, a dished thighsection 34, and an extendable and retractable foot section 36. A seatsection 33 in the form of a smaller dished panel is situated in thespace between head section 32 and thigh section 34 as shown in FIG. 4.Bed 10 of FIGS. 3 and 4 has upper frame 38 upon which sections 32, 34,36 of deck 30 are supported for pivoting or articulating movement. Seatsection 33 is stationary relative to upper frame 38 in bed 10 of FIGS. 3and 4. Deck 30 of FIGS. 3 and 4 is sometimes referred to as a step deckin the art due to the dished shape of some or all of the deck sections32, 33, 34, 36. Additional details of the VERSACARE® bed 10 shown inFIGS. 3 and 4 can be found in Service Manual, VersaCare® Bed, fromHill-Rom, Product P3200/P3201, © 2008 by Hill-Rom Services, Inc. and inU.S. Pat. No. 7,533,429, each of which is hereby incorporated byreference herein for all that it teaches.

As shown in FIG. 3, reader 12 is shown mounted to an underside of aframe member of thigh section 34. Thus, in the illustrative example,reader 12 articulates with thigh section 34 as thigh section 34 pivotsrelative to upper frame 38. In other embodiments, reader 12 is mountedto upper frame 38. Reader 12 may become blocked from view in theillustrative example when the adjacent siderail 46 is moved from theillustrative lowered position up to a raised position. It should beappreciated that each of siderails 44, 46 is movable between raised andlowered positions relative to their respective support structure (e.g.,head section 32 in the case of siderails 44 and upper frame 38 in thecase of siderails 46).

Antennae 13, 14 of FIGS. 3 and 4 are mounted to head section 32 closerto the left side of bed 10 than to the right side. In particular,antenna 13 is mounted to a bottom panel of deck section 32 and antenna14 is mounted to an angled sidewall of deck section 32. Both antennae13, 14 are situated adjacent to a foot end of deck section 32.Similarly, antennae 15, 16 are mounted to thigh section 34 closer to theleft side of bed 10 of FIGS. 3 and 4 than to the right side. Inparticular, antenna 15 is mounted to a bottom panel of deck section 34and antenna 16 is mounted to an angled sidewall of deck section 34. Bothantennae 15, 16 are situated adjacent to a foot end of deck section 34in the illustrative example. The left and right sides of bed 10correspond to left and right sides of a patient lying in bed 10 in asupine position. In some embodiments, strips of hook and loop fasteners(not shown) are used to hold antennae 1114, 1116 in place on therespective deck sections 32, 34.

The reason for locating antennae 13, 14, 15, 16 closer to the left sideof bed 10 is twofold. First, the thickness of each antenna 13, 14, 15,16 is in the range of about ½ inch, give or take a ¼ inch or so, andtherefore, by placing the antennae 13, 14, 15, 16 closer to the leftside of deck 30, a patient positioned on a mattress supported by deck 30is less likely to “feel” the antennae 13, 14, 15, 16 through themattress. Second, incontinence detection pads 60 contemplated by thisdisclosure have RFID tags 64 situated near the left side of the pads 60.Thus, the antennae 13, 14, 15, 16 which emit or radiate energy to powerthe RFID tags 64 and to read the data sent or reflected back from theRFID tags 64 operate more efficiently when they are closer to the RFIDtags 64. Accordingly, it should be appreciated that, in alternativeembodiments of incontinence detection system 20, antennae 13, 14, 15, 16may be located closer to the right side of bed 10 if the incontinencepads 60 of such alternative embodiments have their respective RFID tags64 situated near the right sides of the pads 60 rather than the leftsides. Alternatively or additionally, deck sections 32, 34 may be formedwith recesses in which respective antennae 13, 14, 15, 16 are receivedso that upper surfaces of antennae 13, 14, 15, 16 are generally flushwith upper surfaces of the bottom panel of deck sections 32, 34.

In the embodiment of FIGS. 3 and 4, cables 23 are routed from respectiveantennae 13, 14, 15, 16 to reader 12 through a gap or space 70 definedbetween a foot end of head section 32 and a head end of thigh section34. In the illustrative FIGS. 3 and 4 example, all four cables 23 arerouted through a space between a head end of the seat section 33 and thefoot end of the head section 32. However, some or all of cables 23 mayjust as well be routed through a space between a head end of the thighsection 34 and a foot end of the seat section 33. Regardless of theexact routing path, cables 23 are provided with sufficient slack topermit head section 32 and thigh section 34 to pivot through their fullranges of movement relative to upper frame 38.

Cable 25 is routed from reader 12 to visual indicator 1118 along anunderside of thigh section 34 and foot section 36 as shown in FIG. 3.Because visual indicator 18 is mounted to the portion of foot section 36that extends and retracts, cable 25 is provided with sufficient slack topermit the extension and retraction of foot section 36 through its fullrange of movement. Cable 27 is routed from reader 12 to output port 22along portions of deck 30 and frames 38, 40 as desired. Because outputport 22 is mounted to upstanding portion 50 of base frame 40 and becausereader 12 is mounted to deck 30 or frame 38, as the case may be, whichare able to be raised, lowered and tilted relative to base frame 40,cable 27 is provided with sufficient slack to permit the upper frame 38,along with deck 30, to be raised, lowered and tilted relative to baseframe 40 through its full range of movement.

Suitable cable management devices such as zip ties, hooks, clips,straps, bands, and the like are provided in some embodiments to attachcables 23, 25, 27 to portions of bed 10 at various locations to preventunwanted sagging or movement of cables 23, 25, 27. However, as suggestedabove, some portions of cables 23, 25, 27 should be sufficiently slackto permit movement of the various portions of bed 10 without stretching,pinching or binding the respective cable 23, 25, 27. Reader 12 of FIGS.3 and 4 commands indicator 18 to shine white, green, or amber light toindicate the same information as discussed above in connection withindicator 76 e of bed 10 of FIGS. 1 and 2. Output port 22 of bed 10 ofFIGS. 3 and 4, however, is a ¼ inch jack receptacle as will be discussedin further detail below in connection with FIG. 7.

Referring now to FIGS. 5 and 6, the illustrative PROGRESSA® bed 10 showntherein has similar features as the illustrative VERSACARE® bed 10 ofFIGS. 3 and 4 as well as the bed 10 of FIGS. 1 and 2. Thus, likereference numbers are used to denote like portions of these beds 10 andthe descriptions above are equally applicable except where noted belowin the discussion of bed 10 of FIGS. 5 and 6. In FIG. 5, the foot rail46 at the left side of the bed 10 has been removed so that certainaspects of mattress support deck 30 are more readily visible. Bed 10 ofFIG. 5 has a base 40′ that includes a shroud and the metal frame membersof the base frame covered by the shroud. The arms or links 41 of thelift system of bed 10 of FIG. 5 can also be seen, although the linearactuators that are operated to move arms 41 to raise, lower and tiltupper frame 38 relative to base 40′ are covered by the shroud of base40′.

Deck 30 of FIGS. 5 and 6 has flat panels for its various sections and sois not a step deck. Deck 30 of FIGS. 5 and 6 has a first head sectionportion or panel 32 a and a second head section portion or panel 32 bthat are included in head section 32 of bed 10. As head section 32 ispivotably raised relative to upper frame 38, deck panel 32 a translatesin parallel relation with deck panel 32 b in a direction indicated byarrow 82 in FIG. 5. As head section 32 is pivotably lowered relative toupper frame 38, deck panel 32 a translates in parallel relation withdeck panel 32 b in a direction opposite of arrow 82. First antenna 13 ofincontinence detection system 2 of FIGS. 5 and 6 is coupled to themovable deck panel 32 a in a lower left side corner region thereof.Thus, antenna 13 translates with head section portion 32 a relative tohead section portion 32 b. Cable 23 that extends from antenna 13 toreader 12 includes sufficient slack to accommodate this movement ofantenna 13.

In some embodiments, a pivot axis about which head section 32 of bed 10of FIGS. 5 and 6 pivots relative to upper frame 38 translates toward thehead end of upper frame 38 when head section 32 is raised and translatestoward the foot end of upper frame 38 when head section 32 is lowered.Such movement of the head section pivot axis during raising of headsection 32 further increases a distance between antenna 13 and reader 12which also is accommodated by slack in the respective cable 23.Additional details of a suitable mechanism for translating head sectionportion 32 a relative to head section portion 32 b and for translatingthe head section pivot axis relative to upper frame 38 can be found inU.S. Pat. No. 8,516,634 which is hereby incorporated by reference hereinin its entirety. Further details of bed 10 of FIGS. 5 and 6 can also befound in Service Manual, Progressa™ Bed, From Hill-Rom, Product No.P7500, © 2013 by Hill-Rom Services, Inc.

A seat section 33 of deck 30 of bed 10 can be seen in FIGS. 5 and 6.Seat section 33 is situated longitudinally between the foot end ofportion 32 b of head section 32 and the head end of thigh section 34.Deck 30 of FIGS. 5 and 6 includes a pair of side panels 35, each ofwhich is situated laterally outboard of seat section 33 and thighsection 34. Thus, one of panels 35 is located to the right of decksections 33, 34 and the other of panels 35 is located to the left ofdeck sections 33, 35. Panels 35 and seat section 33 are fixed relativeto upper frame 38 in the illustrative embodiment. Thus, in the lateraldimension of bed 10 of FIGS. 5 and 6, seat and thigh sections 33, 34 arenot as wide as head and foot sections 32, 36. Accordingly, antenna 16mounted to thigh section 34 of FIGS. 5 and 6 is located further from theleft side of bed 10 than is antenna 13. The same can be said forantennae 14, 15 that are mounted to seat section 33. That is antennae14, 15, 16 are located at different distances from the left side of bed10 (or the left side of deck 30) of FIGS. 5 and 6 as compared to antenna13. On seat section 33, antenna 14 is closer to the left side than isantenna 15. As discussed above, the placement of antennae 13, 14, 15, 16on deck 30 is a matter of trial and error. In alternative embodiments,one or more of antennae 13, 14, 15, 16 are mounted to panel 35.

In the illustrative example of FIGS. 5 and 6, cables 23 are all routedfrom respective antennae 13, 14, 15, 16 to reader 12 through a space orgap 70′ formed adjacent to a junction between the panel 35 at the leftside of bed 10, a left head end corner region of seat section 33, and aleft foot end corner region of panel 32 b of head section 32. In theillustrative example of FIGS. 5 and 6, reader 12 is mounted to anundersurface of a longitudinal frame member 86 of upper frame 38. Inother embodiments, reader 12 is mounted to a side surface of framemember 86. The side surface of frame member 86 in such embodiments maybe the inwardly facing side surface (i.e., the one facing toward acenter of bed 10) or the outwardly facing side surface (i.e., the onethat can be seen in FIG. 5 facing away from the center of bed 10).

Foot section 36 of bed 10 of FIGS. 5 and 6 is also extendable andretractable. Thus, cable 25 shown in FIG. 5 has sufficient slack toaccommodate the extension and retraction of foot section 36. Output port22 of FIG. 5 is mounted to upper frame 38 to be raised, lowered, andtilted therewith. Thus, extra slack does not need to be provided in thatcable 27 of FIG. 5 that extends between reader 12 and output port 22.Thus, in FIG. 5, cable 27 is shown as being situated against theinwardly facing side surface of upper frame member 86 along a majorityof its length.

Referring now to FIG. 7, a diagrammatic view of bed 10 and incontinencedetection system 20 is provided. Bed 10 of FIG. 15 has a mattress 100(aka a patient support surface or just a surface) supported on decksections 32, 33, 34, 36 of deck 30. Incontinence detection pad 60 havingan RFID tag 64 is situated between a patient and mattress 100. Pad 60 isgenerally located beneath the patient's buttocks and upper thighs so asto increase the likelihood of absorbing and detecting incontinenceexpelled by the patient.

A head section motor 90 for pivotably raising and lowering head section32 and a thigh section motor 92 for pivotably raising and lowering thighsection 34, such as through flanges, brackets, and/or linkages attachedto frame 38 and sections 32, 34, are shown diagrammatically in FIG. 7.Motors 90, 92 are included in respective linear actuators in someembodiments of bed 10. Bed control circuitry 72 commands operation ofmotors 90, 92 in response to user inputs on bed as is known in the art.

As indicated diagrammatically in FIG. 7, antenna 16 is located a firstdistance d₁ away from RFID tag 64, antenna 15 is located a seconddistance d₂ away from RFID tag 64, antenna 14 is located a thirddistance d₃ away from RFID tag, and antenna 16 is located a fourthdistance d₄ away from RFID tag 64. One of antennae 13, 14, 15, 16 areestablished as a transmit antenna that is controlled by reader 12 toemit energy through mattress 100 to RFID tag 64 and tag 64 responds withits data back through mattress 100 to another one of antennae 13, 14,15, 16 which is established as a receive antenna. Reader 12 is also ableto write data to RFID tag 64 via the established transmit antennae 13,14, 15, 16. Thus, once pad 60 becomes wet a particular bit of data isset in memory of RFID tag 64 (more particularly, an RFID chip of tag 64)and when reader 12 processes the data received from RFID tag 64, it isable to determine whether the pad 64 is wet or not wet (moreparticularly, not sufficiently wet to cause the particular bit to getset).

If reader 12 determines that pad 60 is wet, a second bit (aka a killbit) is set in RFID tag 64 by reader 12 via the established transmitantennae 13, 14, 15, 16. Once the kill bit is set in RFID tag 64, itremains unchanged thereafter. If pad 60 dries out after having been wet,reader 12 will see that the kill bit is still set when it receivessubsequent data from RFID tag 64 such that the particular pad 60 shouldnot be re-used. In some embodiments, reader 12 sends an alert toindicate that the pad 60 is a “bad” pad that should not be used becauseit has been previously soiled with wetness. In other embodiments, reader12 simply causes visual indicator 18 to emit white light indicating thata “good” pad is not being read by the reader 12.

If desired, caregivers may place multiple pads 60 on mattress 100beneath the patient. For example, it is not uncommon for two pads 60 tobe used to increase the area of incontinence absorption beneath apatient. The reader 12 is able to read backscattered data from multipleRFID tags 64 of multiple pads 60 according to this disclosure. Sometransmit/receive antennae combinations, for example, may read one RFIDtag 64 and other transmit/receive antennae combinations may read anotherRFID tag 64, for example. Some transmit/receive antennae combinationsmay read multiple tags 64. Reader 12 initiates an alert, as describedelsewhere herein, if any one or more of the multiple incontinencedetection pads 60 indicate that they are wet.

As further indicated diagrammatically in FIG. 7, reader 12 has wirelesscommunication capability. In the illustrative example, reader 12communicates wirelessly with a wireless access point 118. The wirelesscommunication between reader 12 and wireless access point 118 isbidirectional in some embodiments. That is, wireless messages can besent and received by reader 12 and by wireless access point 118.Wireless access point 118 is coupled to a network 120 so that messagesfrom reader 12 received by wireless access point 118 are ultimately ableto be transmitted through network 120 to other computer devices of othersystems. For example, messages from reader 12 are communicated to anurse call system 122 in the illustrative example. The block 122 labelednurse call system in FIG. 7 is intended to represent the variousservers, computers, room stations, staff stations, and master nursestations as well as any additional associated infrastructure associatedwith a nurse call system. Such nurse call systems and associatedinfrastructure are shown and described, for example, in U.S. Pat. Nos.9,411,934 and 8,598,995 which are hereby incorporated by referenceherein.

As shown diagrammatically in FIG. 7, output port 22 is electricallycoupled via a wired connection 124 to an input port 126 located on awall 128 in a hospital room. In some embodiments, wall 128 may comprisea room wall of a healthcare facility. In other embodiments, wall 128 maycomprise a panel of a piece of architectural equipment such as aheadwall unit, a bed locator unit, a column, an arm, a service chase orthe like that are installed in a hospital room. Input port 126 iscoupled to network 120 via suitable infrastructure such as cabling,routers, gateways, and the like. Thus, data from reader 12 of system 20communicated to port 126 from port 22 also can be received by computerdevices of other systems such as nurse call system 122. Thus, in theillustrative example, reader 12 is able to communicate data from system20 via a wired datalink 124 and a wireless datalink between reader 12and wireless access point 118.

In some embodiments contemplated herein, reader 12 of incontinencedetection system 20 is equipped with an 802.11 wireless communicationcapability for communication with wireless access point 118 which is, inturn, connected via network 120 to a remote computer or server of aClinical Workflow Solutions (CWS) medical data management system 122.CWS system 122 may or may not be included as part of nurse call system122. Block 122 in FIG. 7 is intended to represent CWS system eitherindividually or collectively with the nurse call system. In suchembodiments, reader 12 send the tag identification (ID) and an encryptedID, both of which are received by reader 12 from tag 64 of pad 60, tothe CWS system 122 for remote validation of the pad 60 placed on the bed10. If more than one pad 60 is on bed 10, then reader 12 receives morethan one tag ID and more than one encrypted ID. The CWS system 122 thenperforms decryption remotely and compares the tag ID and the dataderived from decrypting the encrypted ID from the tag 64 to complete thevalidation. If desired, the data sent from the reader 12 is protectedagainst transmission errors corrupting the data with standard InternetProtocol error checking algorithms and/or additional error detectioncould be applied by the reader 12 at the bed 10.

By moving the validation operation to a remote site, such as a computerof CWS system 122, having internet connectivity results in a number ofadvantages. Firstly, the processor of reader 12 at the bed 10 may nothave the computational resources either in terms of memory or CPU cyclesto accomplish the decryption locally. Secondly, the encryption algorithmcan be changed at will and the algorithm used determined by tag ID sothe deployment in the field is seamless. The encryption details andprivate keys may be managed by an online connection to a secure serverat another facility (e.g., a server at the entity which manufactures orsells system 20 and/or bed 10), which enables the modification of theprivate key on an as-needed basis, a periodic change in private key orthe wholesale replacement of the encryption algorithm in a securefashion. In this way, the data generated for pad validation is done inan entirely secure fashion, and may be done on an as needed basis. If itis detected that the private key has become compromised, a new privatekey may be instituted and the pad serial numbers/private key maintainedin a database at the CWS server 122 for pad validation.

The present disclosure also contemplates embodiments in which eachincontinence detection pad 60 has the same unique authentication codestored in the respective RFID tag 64. One example of such a uniqueauthentication code is the electronic product code (EPC) that isestablished by EPCglobal Inc. according to the EPCglobal Tag DataStandard. Thus, each RFID tag 64 of each pad 60 that is authorized foruse in the incontinence detection system 20 will have stored in itsmemory the same authentication code (hereinafter referred to as “EPC”).In response to the RFID tag 64 of pad 60 being energized or scanned bythe reader 12, the EPC is transmitted to the reader 12 from the RFID tag64 as backscattered data along with other data such as data indicatingwhether the pad 60 is dry (e.g., unsoiled) or wet (e.g., soiled) and, insome embodiments, along with the tag ID. Prior to being assembled intopad 60, the RFID chip of tag 64 may have its own EPC in someembodiments. In such embodiments, the EPC of the RFID chip isoverwritten with the pad-specific EPC during the manufacturing processof the pad 60. The overwriting of the EPC may occur before or after theRFID tag 64 is attached to one of the layers, such as backsheet 200, ofpad 60 during manufacture. In use thereafter, the RFID tag 64 includesthe pad-specific EPC in any responses it sends to reader 12.

If the reader 12 receives a transmission that does not include thepad-specific EPC that it should receive to indicate that an authorizedpad 60 is being read by the reader 12, then the reader 12 ignores thetransmission (which is referred to herein as an “unauthorizedtransmission”) after making the determination that the EPC received fromthe RFID tag does not match the pad-specific EPC. Thus, by ignoring theunauthorized transmission, no message regarding the wet or dry status ofan unauthorized pad is output by the reader 12. In some embodiments,however, the reader 12 may transmit or output other messages regardingthe attempted use of an unauthorized pad in system 20 as will be furtherdiscussed below.

To make the determination as to whether a pad 60 is authorized orunauthorized, the reader 12 also has stored in its memory thepad-specific EPC for comparison purposes to the data received from theRFID tag 64. In some embodiments, if the reader 12 receives anunauthorized transmission, a warning message is transmitted from thereader 12 for display on bed 10 and/or on a device (e.g., master nursestation computer, room station, staff station, caregiver phone, pager,etc.) of nurse call system 122 and/or on some other device (e.g., smartphone, computer, etc.) included in, or accessible by, the network of thehealthcare facility to notify one or more caregivers that anunauthorized pad is being used on bed 10. In some embodiments, thenotification includes instructions to replace the unauthorized pad withan authorized pad 60.

If desired, the warning message from reader 12 regarding the use of anunauthorized pad on bed 10 is also transmitted to the manufacturerand/or seller of authorized pads 60. The manufacturer and/or seller ofauthorized pads 60 is then able to contact the healthcare facilityregarding its use of unauthorized pads and to prompt the purchase ofauthorized pads 60. Optionally, the warning message from the reader 12regarding the use of an unauthorized pad on bed 10 results in anotification to personnel of the healthcare facility advising that anywarranties relating to incontinence detection system 20 may potentiallybecome void as a result of the attempted use of unauthorized pads 60 onbed 10. Such a notification from the reader 12 regarding warrantyvoiding may be displayed on bed 10 and/or the various devices notedabove, and also may be sent, for example, directly to other personnel(e.g., purchasing, legal, etc.) of the healthcare facility via e-mail,text message, or the like.

It is further contemplated by this disclosure that a “select” functionof RFID tags is used to prevent unauthorized transmissions to the reader12. According to the select function, a requesting device, such asreader 12, has the ability to send out a broadcast transmission message(aka a “select broadcast”) containing the pad-specific EPC to all nearbydevices (e.g., those within reception range of reader 12). The receivingdevices including RFID tags (or other similar communication circuitrywith the select function) that do not have the pad-specific EPC storedtherein will, thereafter, not respond to any requests from therequesting device (e.g., reader 12) either indefinitely or for athreshold amount of time. Thus, by having the reader 12 transmit theselect broadcast out with the pad-specific EPC, only authorized pads 60with the pad-specific EPC stored therein will respond to subsequentrequests from the reader 12, for at least the threshold time durationand/or until another select broadcast is transmitted to reset thethreshold time.

It should be understood that use of authentication codes in incontinencedetection pads, as just described above, may be used in any of theembodiments of incontinence detection pads described herein. Otherexamples of incontinence detection pads in which authentication codesmay be used according to this disclosure can be found in U.S. PatentApplication Publication Nos. 2018/0021184 A1; 2017/0246063 A1;2017/0065464 A1; 2016/0374626 A1; and 2014/0276504, and in U.S.Provisional Application No. 62/660,558, filed Apr. 20, 2018, each ofwhich is hereby incorporated by reference herein in their entirety forall that they teach to the extent not inconsistent with the presentdisclosure which shall control as to any inconsistencies.

System 20 and bed 10 may be used in home healthcare and other marketsoutside a traditional hospital or other healthcare facility. For suchmarkets, the reader 12 may be constructed with a very limitedfunctionality microprocessor by having the high compute resourceintensity operations, such as decryption algorithms, accomplishedremotely via any available internet connection. As a collateral benefit,a service is contemplated to automatically bill and send moreincontinence pads to a customer (via prior arrangement), therebyenabling e-commerce business using existing hardware connections. Thus,a server of CWS system 122 or a server at a remote facility may performpad usage data collection, may perform billing functions, and/or maygenerate inventory management data, as well as provide othernotifications to hospitals or home users about incontinence detectionpad 60 usage. For example, such usage data may include number of pads 60used per day, week, and/or month; average amount of time before a drypad becomes soiled; average amount of time after soiling before the wetpad is removed and/or replaced with a dry pad; and number of padsremaining from prior shipment quantity for usage.

In some embodiments, such as the illustrative embodiments of FIGS. 3, 5,and 7, output port 22 comprises a female ¼ inch receptacle which isconfigured for receipt of a male ¼ inch jack (sometimes referred to as aphono jack). Input port 126 is also a female ¼ inch receptacle thatreceives a male ¼ inch jack in some embodiments. In such embodiments,the data communicated via such ¼ inch receptacles and ¼ inch jacks arebinary in nature to indicate simply whether incontinence detection pad60 is wet or not wet. Such binary signals are sometimes referred to ascontact closures because, when in a high state (e.g., logic level 1),they close a relay coupled to port 126 which, in turn, sends a signal tonurse call system 122. In some embodiments, the closure of the relayoccurs at the low sate (e.g., logic level 0) rather than the high statedepending upon the relay design. In either case, the signal to nursecall system 122 is a simple on/off or binary signal. In someembodiments, the relays are wired directly into the nurse call system122 without involving network 120. If desired, a more sophisticatedoutput port 22 and input port 126 may be used. For example, RJ-45connectors, 37-pin connectors, RS-232 connectors and the like (e.g.,multi-pin/multi-port or multi-contact) devices may be used as ports 22,126 in some embodiments according to this disclosure.

In some embodiments, reader 12 energizes antennae 13, 14, 15, 16 to scanfor RFID tag 64 using a linear frequency hopping scheme that cyclesthrough fifty frequencies between a lower frequency limit and an upperfrequency limit. In some embodiments, the lower frequency limit is about902 Megahertz (MHz) and the upper frequency limit is about 928 MHz. Thefrequency hopping scheme is non-consecutive and the hops are arranged ingroups of five that start near the bottom of the frequency band and hopin approximately 5 Megahertz (MHz) jumps to near the top of thefrequency band, then the hops go back near the bottom of the frequencyband until all fifty frequencies are used. No frequency is used twiceuntil all fifty frequencies have been used, at which time the sequencerestarts. In some embodiments, the sequence of frequencies is asfollows: 902.75; 907.75; 912.75; 917.75; 922.75; 906.75; 911.75; 916.75;921.75; 926.75; 904.75; 909.75; 914.75; 919.75; 924.75; 903.25; 908.25;913.25; 918.25; 923.25; 907.25; 912.25; 917.25; 922.25; 927.25; 905.25;910.25; 915.25; 920.25; 925.25; 903.75; 908.75; 913.75; 918.75; 923.75;905.75; 910.75; 915.75; 920.75; 925.75; 904.25; 909.25; 914.25; 919.25;924.25; 906.25; 911.25; 916.25; 921.25; and 926.25. However, it shouldbe appreciated that other sequences of fifty frequencies may be used inthe frequency hopping scheme in other embodiments. In some embodiments,the sequence of fifty frequency hops is set arbitrarily by software.

As discussed above, each antenna 13, 14, 15, 16 is cycled through asbeing the transmit antenna and each of the remaining three antennae 13,14, 5, 16 are cycled through as being the receive antenna. In thisregard, the following twelve transmit and receive antenna combinationsare provided in some embodiments: antenna 13 transmits and antenna 14receives, followed by antenna 16 receives, followed by antenna 16receives; antenna 14 transmits and antenna 13 receives, followed byantenna 15 receives, followed by antenna 16 receives; antenna 15transmits and antenna 13 receives, followed by antenna 14 receives,followed by antenna 16 receives; and antenna 16 transmits and antenna 13receives, followed by antenna 14 receives, followed by antenna 15receives. In this scenario, there is only one transmit antenna and onereceive antenna at any given instance during operation of reader 12. Ineach case, reader 12 uses the next available frequency in the hoppingsequence when cycling through the transmit and the receive antennaecombinations.

In the illustrative example, a multiple input multiple output (MIMO)antenna control scheme is not used because only one antenna transmits atany given time and only one other antenna is established as the receiveantenna at any given time. However, it is within the scope of thisdisclosure for multiple output antennae (i.e., multiple transmitantennae that transmit substantially simultaneously) and/or multipleinput antennae (i.e., multiple receive antennae that are established asreceive antennae) to be established by reader 12 in other embodiments.For example, antennae 13, 14 may be established by reader 12 as transmitantenna and antennae 15, 16 may be established by reader 12 as receiveantennae. All 2-by-2 combinations of antennae 13, 14, 15, 16 arecontemplated. Alternatively, three of antennae 13, 14, 15, 16 may beestablished as transmit antennae and the remaining one antenna 13, 14,15, 16 may be established as the receive antenna. All 3-by-1combinations of antennae 13, 14, 15, 16 are contemplated. Furtheralternatively, one of antenna 13, 14, 15, 16 may be established as thetransmit antennae and the remaining three antenna 13, 14, 15, 16 may beestablished as receive antennae. All 1-by-3 combinations of antennae 13,14, 15, 16 are contemplated. In some embodiments, incontinence detectionsystem 20 may have only three antennae or may have more than fourantennae. All permutations and combinations of receive and transmitantennae designations are contemplated by this disclosure.

As shown in FIG. 8, which includes four pages, a portion of thecircuitry of reader 12 includes a bistatic radio frequency (RF) switchmatrix 140 which is used to select which antennae 13, 14, 15, 16 is thetransmit antenna and which is the receive antennae. Other portions ofthe circuitry of reader 12 is shown and described in InternationalPatent Application No. PCT/US2016/062167, particularly in connectionwith FIGS. 29A-C thereof. Illustrative bistatic RF switch matrixincludes two model no. SKY 13596 double-pole, double-throw (DPDT)switches 142 and two model no. SKY 13330 single-pole, double-throw(SP2T) switches 144, each of which is available from Skyworks Solutions,Inc. of Woburn, Mass. The circuitry of FIG. 8 also includes a set offour HSMF-C165 miniature bi-color surface mount ChipLED's 146 which eachhave a red diode and a green diode and which are available from AvagoTechnologies of San Diego, Calif. The red and green diodes of ChipLED's146 are illuminated to indicate the operational status of the respectiveantenna 13, 14, 15, 16. For example, the green diode is illuminated whenthe respective antenna 13, 14, 15, 16 is operating as a transmit antennaor a receive antenna and the red diode is illuminated when therespective antenna 13, 14, 15, 16 is dormant and not being used aseither a transmit or receive antenna. Further details of the circuitryassociated with the bistatic RF switch matrix 140 are apparent in FIG. 8and need not be discussed in detail.

According to this disclosure, the bistatic RF switch matrix 140 isoperated in a full cycle scanning mode so that each of the first,second, third and fourth antenna 13, 14, 15, 16 is selectively chosen tobe established as the transmit antenna and each of the remaining threeantenna are selectively cycled through to be the receive antenna suchthat twelve transmit antenna and receive antenna combinations areoperated. During the full cycle scanning mode, the transmit antenna andreceive antenna combinations that produce valid reads of one or moreRFID tags 64 of respective one or more incontinence detection pads 60that are bed 10 are stored. In some embodiments, a modified cyclescanning mode is then determined for operation of the bistatic RF switchmatrix 140 based on the valid reads such that only transmit antenna andreceive antenna combinations that produced valid reads of the one ormore RFID tags 64 are cycled through for a predetermined number ofcycles, after which the bistatic RF switch matrix 140 is once againoperated in the full cycle scanning mode.

The full cycle scanning mode may operate for several iterations so that,for example, ten reads of all possible antenna 13, 14, 15, 16transmit/receive combinations are made before determining thosecombinations to be used in the modified cycle scanning mode. Thepredetermined number of iterations of the modified cycle scanning modemay be more or less than ten, for example. During the modified cyclescanning mode, the frequency hopping scheme described above continues tobe used, just on a lesser number of transmit and receive antennae 13,14, 15, 16 combinations. In some embodiments, if no valid reads of thepassive RFID tag 64 are detected during the full cycle scanning mode,then the bistatic RF switch matrix 140 continues to operate in the fullcycle scanning mode until at least one valid read is detected, afterwhich the bistatic RF switch matrix 140 is operated in the modifiedcycle scanning mode.

Antennae 13, 14, 15, 16 of reader 12 are operated at low power (e.g.,less than or equal to 1 Watt) to meet U.S. Federal CommunicationsCommision (FCC) regulations for maximum permissible exposure (MPE)limits. The MPE limits specified by the FCC are dependent upon frequencyand power density limits which are specified as an average value over asix minute period. In the 902 MHz-928 MHz frequency band, the powerdensity limit is 0.601 milliWatts (mW)/cm² over any six minute period oftime. In some embodiments, a delay period is provided betweentransmissions from antennae 13, 14, 15, 16 to keep within the MPElimits.

Referring now to FIG. 9, a backsheet 200 of an incontinence detectionpad that is suitable for use with incontinence detection system 20 isshown. Backsheet 200 may replace the backsheets of any of theincontinence detection pad embodiments shown in InternationalApplication No. PCT/US2016/062167, such as those shown in FIGS. 8A-8Dand 31-39, for example. Backsheet 200 is rectangular in shape and hasfirst and second electrode traces 202, 204 printed thereon. Electrodetraces 202, 204 are sometimes referred to herein as electrodes 202, 204.

Electrode 202 has a first straight line segment portion 206, a secondstraight line segment portion 208 that is substantially perpendicular toportion 206, a third straight line segment portion 210 which issubstantially perpendicular to second portion 208 and which couples toRFID tag 64, a fourth straight line segment portion 212 that issubstantially parallel with portion 208, a fifth straight line segmentportion 214 which is parallel with portions 206, 210, a sixth straightline segment portion 216 which is parallel with portions 208, 212, and aseventh straight line segment portion 218 which is parallel withportions 206, 210, 214 and aligned with portion 206. The transitionsbetween portions 206, 208, 210, 212, 214, 216, 218 are rounded such ashaving a radius of about 51.5 mm, although the radius between portions208, 210 is about 36.5 mm and the radius between portions 210, 212 iseven less than that. The rounded portions of trace 202 each extend overan arc of about 90°.

Electrode 204 has a first straight line segment portion 220, a secondstraight line portion 222 that is substantially perpendicular to portion220, a third straight line segment portion 224 that extends from portion222 in perpendicular relation therewith, a fourth straight line segmentportion 226 that is substantially parallel with portion 220, a fifthstraight line segment portion 228 that is substantially parallel withportion 226 and offset therefrom, and a sixth straight line segmentportion 230 that, when extended, forms an included angle 232 of about45° with portion 226. Portion 230 provides and inclined transitionbetween portions 226, 228. Portion 228 also couples electrically withRFID tag 64. The transition between portion 220 and portion 222 and thetransition between portion 224 and portion 226 is rounded over an arc ofabout 90° such as having a radius about 51.5 mm.

Portion 206 of trace 202 is substantially parallel with, and situatedbetween, portions 220, 226 of trace 204. Portion 226 of trace 204 issubstantially parallel with, and situated between, portions 206, 214 oftrace 202. Similarly, portion 208 of trace 202 is substantially parallelwith, and situated between, portions 222, 224 of race 204. Portion 224of trace 204 is parallel with, and situated between, portions 208, 216of trace 202. Electrodes 202, 204 are printed on backsheet 200 andcomprise a conductive ink such as carbon ink, silver ink, or the like.In some embodiments, the thickness of traces 202, 204 is about 3.0mm+/−0.5 mm.

Perpendicular distances 234 between portion 206 of electrode 202 andportion 220 of electrode 204 and between portion 214 of electrode 202and portion 226 of electrode 204 is about 127.0 mm in the illustrativeexample. A perpendicular distance 236 between portion 206 of electrode202 and portion 226 of electrode 204 is about 317.0 mm in theillustrative example. Thus, the distance 236 between portions 206, 226is more than twice that of each of distances 234. In particular, theratio of distance 236 to 234 is about 317/127=2.496.

Perpendicular distances 238 between portion 208 of electrode 202 andportion 222 of electrode 204 and between portion 216 of electrode 202and portion 224 of electrode 204 is about 77.0 mm in the illustrativeexample. A perpendicular distance 240 between portion 208 of electrode202 and portion 224 of electrode 204 is about 537.0 mm in theillustrative example. Thus, the distance 240 between portions 208, 224is more than six times that of each of distances 238. In particular, theratio of distance 236 to 234 is about 537/77=6.974.

Long side edges 242 of backsheet 200 have lengths of about 900.0 mm andshort end edges 244 have lengths of about 750.0 mm in the illustrativeexample. The long dimension of backsheet 200 is sometimes referred to asthe machine direction (MD) and the short dimension of backsheet 200 issometimes referred to as the cross direction (CD). Distance 236 betweenthe electrode segment portions 206, 226 is greater than 30% and greaterthan 40% of the 750.0 mm distance defined between the long sides 242 ofthe layer 200. In particular, the ratio of distance 236 to 750.0 mm is317/750=0.423 or 42.3% on a percentage basis. Distance 240 between theelectrode segment portions 208, 224 is greater than 40% and greater than50% of the 900.0 mm distance defined between the short ends 242 of thelayer 200. In particular, the ratio of distance 240 to 900.0 mm is537/900=0.597 or 59.7% on a percentage basis.

Distances 236 between electrode portions 206, 226 and distance 240between electrode portions 208, 224 provide the incontinence detectionpad 60 having backsheet 200 with a relative large central region that isdevoid of any electrode portions. This represents an improvement overthe electrode trace geometry of the incontinence detection pad disclosedin International Patent Application No. PCT/US2016/062167,particularlyin connection with FIG. 31 thereof. During testing, it was found thatpatients having a gel or ointment applied to the patient's buttocksand/or sacral region could cause an electrically conductive path to beformed between the electrode segments in the central region of the pad.The gel or ointment was conducting the electricity between theelectrodes thereby causing false positives with regard to incontinencedetection. Thus, spacing electrodes 206, 226 farther apart and spacingelectrodes 208, 224 father apart than in the prior art pad, the chancesof the gel or ointment on a patient closing the circuit betweenelectrode traces 202, 204 is reduced significantly.

Backsheet 200 includes a sacrificial trace 246 in an end region adjacentto one of edges 244. Sacrifical trace 246 is left over from an electrodetrace of a next adjacent backsheet 200 during a manufacturing process asis described in further detail in International Patent Application No.PCT/US2016/062167, particularly in connection with FIG. 36 thereof.Sacrificial trace 246 is somewhat U-shaped or C-shaped. An RFID tag footprint 248 in the form of a dashed rectangle is printed on backsheet 200as shown in FIG. 9. Portion 210 of electrode 202 and portion 228 ofelectrode 204 extended into foot print 248 for coupling electrically toRFID tag 64. Foot print 248 delineates an alignment zone or region ofbacksheet 200 within which RFID tag 64 can be placed and form properelectrical contacts with portions 210, 228 of electrodes 202, 204. InFIG. 9, an enlarged bubble to right of backsheet 200 shows RFID tag 64installed on backsheet 200 within the foot print 248.

Still referring to FIG. 9, a substantially rectangular phantom box 250is shown on backsheet 200 to delineate the general location of aperimeter of an absorbent core of an incontinence detection pad 60 inwhich backsheet 200 is included. A set of dashed lines 252 adjacent oneof edges 244 indicates the locations at which the incontinence detectionpad having backsheet 200 is folded in the machine direction. It shouldbe noted that the two fold lines 252 on the right side of backsheet 200pass to the right and left of foot print 248 and the RFID tag 64contained therein. Thus, the machine direction folds 252 are oriented sothat the RFID tag 64 is not folded when the associated incontinencedetection pad 60 is folded. Backsheet 200 also has an additionalregistration mark 254 that is used during the manufacture of theincontinence detection pad in which backsheet 200 is included.

Although certain illustrative embodiments have been described in detailabove, variations and modifications exist within the scope and spirit ofthis disclosure as described and as defined in the following claims.

The invention claimed is:
 1. An incontinence pad comprising: anabsorbent material; an electrical sheet adjacent the absorbent material;the electrical sheet comprising: a layer of material shaped generally asa rectangle having first and second long sides and first and secondshort sides, an RFID tag coupled to the layer closer to the first shortside than the second short side, and first and second electrodes on thelayer and electrically coupled to the RFID tag, the first and secondelectrodes including first, second, third and fourth electrode segmentsthat are generally parallel with the first and second long sides of thelayer, the second and third electrode segments being situated betweenthe first and fourth electrode segments, the second and third electrodesegments being spaced apart by a first distance that is at least twice asecond distance defined between the first and second electrode segmentsand between the third and fourth electrode segments; wherein the RFIDtag includes a memory location, wherein an authentication code is storedin the memory location and is configured to cause a reading system toalert based on the detection of fluid; and wherein the RFID tag includesa transmitter configured to transmit a signal indicating the presence offluid, wherein the transmitter is further configured to transmit theauthentication code.
 2. The incontinence pad of claim 1, wherein theRFID tag comprises a passive RFID tag.
 3. The incontinence pad of claim1, wherein the authentication code comprises an electronic product code.4. The incontinence pad of claim 1, wherein the layer of materialcomprises a fluid resistant backsheet layer.
 5. The incontinence pad ofclaim 4, further comprising a fluid permeable topsheet layer.
 6. Theincontinence pad of claim 1, wherein the first and second electrodescomprise conductive traces.
 7. The incontinence pad of claim 5, whereinthe conductive traces comprise conductive ink printed on the layer ofmaterial.
 8. An incontinence detection system comprising an incontinencedetection pad for placement beneath a person to be monitored, theincontinence detection pad including an electrical sheet comprising alayer of material shaped generally as a rectangle having first andsecond long sides and first and second short sides, an RFID tag coupledto the layer closer to the first short side than the second short side,and first and second electrodes on the layer and electrically coupled tothe RFID tag, the first and second electrodes including first, second,third and fourth electrode segments that are generally parallel with thefirst and second long sides of the layer, the second and third electrodesegments being situated between the first and fourth electrode segments,the second and third electrode segments being spaced apart by a firstdistance that is at least twice a second distance defined between thefirst and second electrode segments and between the third and fourthelectrode segments, the RFID tag storing an authentication code which iscommon to all incontinence detection pads that are authorized for use inthe incontinence detection system, a reader having circuitry in whichthe authentication code is also stored, and at least one antenna coupledto the reader, wherein the reader is operable to send a request to theRFID tag via the at least one antenna and to read via the at least oneantenna data emitted from the RFID tag in response to the request, thereader is configured to confirm that the incontinence detection pad isan authorized incontinence detection pad by determining that the datareceived from the RFID tag includes the authentication code, wherein thereader is configured to transmit a message indicating that theauthorized incontinence detection pad is wet if the data received fromthe RFID tag indicates that the incontinence detection pad is wet,wherein the reader does not transmit the message if the data does notinclude the authentication code.
 9. The incontinence detection system ofclaim 8, wherein the authentication code comprises an electronic productcode (EPC).
 10. The incontinence detection system of claim 8, whereinthe request to the RFID tag from the reader also includes theauthentication code and the RFID tag only responds to the request if theauthentication code is included in the request from the reader.
 11. Theincontinence detection system of claim 8, wherein the RFID tag comprisesa passive RFID tag that emits the data as backscattered data.
 12. Theincontinence detection system of claim 11, wherein the backscattereddata includes pad status data indicating whether the incontinencedetection pad is dry or wet.
 13. The incontinence detection system ofclaim 12, wherein the backscattered data further includes a tagidentification (ID) for the passive RFID tag.
 14. The incontinencedetection system of claim 8, wherein the reader is configured totransmit a warning message if the data received from the RFID tag doesnot include the authentication code, the warning message comprising anotification indicating that an unauthorized incontinence detection padis being used with the patient.
 15. The incontinence detection system ofclaim 14, wherein the warning message is transmitted from the reader fordisplay on a patient bed on which the patient is supported.
 16. Theincontinence detection system of claim 15, wherein the reader and the atleast one antenna are coupled to the bed.
 17. The incontinence detectionsystem of claim 14, wherein the warning message is transmitted from thereader to at least one remote computer device.
 18. The incontinencedetection system of claim 17, wherein the at least one remote computerdevice comprises one or more of the following: a master nurse station, aroom station, a staff station, a caregiver phone, a pager, a smartphone, or a computer.
 19. The incontinence detection system of claim 14,wherein the warning message includes instructions to replace theunauthorized pad with an authorized pad.
 20. The incontinence detectionsystem of claim 14, wherein the reader is configured to transmit anotification regarding the use of an unauthorized pad with the patientto a manufacturer or a seller of authorized incontinence detection pads.21. The incontinence detection system of claim 14, wherein the reader isconfigured to transmit a notification to personnel of the healthcarefacility advising that any warranties relating to the incontinencedetection system may potentially become void as a result of theattempted use of an unauthorized pad with the patient.
 22. A method ofmanufacturing a plurality of incontinence detection pads, the methodcomprising receiving a plurality of RFID tags each having achip-specific electronic product code (EPC) code stored in a memory ofthe respective RFID tag, overwriting the chip-specific EPC with apad-specific EPC in each of the plurality of RFID tags such that eachRFID tag has a common pad-specific EPC stored in its respective memory;and coupling each RFID tag to a first layer of a plurality of layers ofa corresponding one of the plurality of incontinence detection pads,wherein each incontinence detection pad of the plurality of incontinencedetection pads includes an electrical sheet comprising a layer ofmaterial shaped generally as a rectangle having first and second longsides and first and second short sides, an RFID tag coupled to the layercloser to the first short side than the second short side, and first andsecond electrodes on the layer and electrically coupled to the RFID tag,the first and second electrodes including first, second, third andfourth electrode segments that are generally parallel with the first andsecond long sides of the layer, the second and third electrode segmentsbeing situated between the first and fourth electrode segments, thesecond and third electrode segments being spaced apart by a firstdistance that is at least twice a second distance defined between thefirst and second electrode segments and between the third and fourthelectrode segments.
 23. The method of claim 22, wherein overwriting thechip-specific EPC with the pad-specific EPC of each of the plurality ofRFID tags occurs prior to the coupling of each RFID tag to therespective first layer.
 24. The method of claim 22, wherein overwritingthe chip-specific EPC with the pad-specific EPC of each of the pluralityof RFID tags occurs after the coupling of each RFID tag to therespective first layer.
 25. The method of claim 22, wherein theplurality of layers of each of the plurality of incontinence detectionpads includes an absorbent layer and further comprising covering theRFID tag and at least a portion of the first layer of each incontinencedetection pad with the respective absorbent material.
 26. The method ofclaim 22, wherein coupling each RFID tag to the respective first layercomprises coupling each RFID tag to a respective pair of conductiveelectrodes supported by the corresponding first layer.
 27. The method ofclaim 22, wherein the plurality of RFID tags comprises passive RFIDtags.
 28. The method of claim 22, wherein the first layer of each of theplurality of incontinence detection pads comprises a fluid resistantbacksheet layer.
 29. The method of claim 22, wherein the plurality oflayers of each incontinence detection pad of the plurality ofincontinence detection pads further comprises a fluid permeable topsheetlayer.